Preparation of allylic esters with palladate and platinate catalysts

ABSTRACT

Tetrahalopalladate and tetrahaloplatinate catalysts effectively catalyze the preparation of allyl esters of carboxylic acids in the reaction between allyl halides and salts of carboxylic acids.

United States Patent Brady 1 Oct. 24, 1972 [S4] PREPARATION OF ALLYLICESTERS [56] References Cited gl'g lifgAsl rldsADATE AND PLATINATE UNITEDSTATES PATENTS 3,360,548 12/1967 Clark et al ..260/491 [72] Invent BradyBartlesvne Okla 3,358,016 12/1967 Kohll et a1. ..260/491 [73] Assignee:Phillips Petroleum Company 3,534,087 10/ 1970 Leften et al. ..260/491[22] Filed: 1971 Primary Examiner-Vivian Garner [21] Appl. No.: 108,617Attorney-Young and Quigg 52 U S Cl 260/491 260/410 9 N 260/468 R [57] CT1 I R, I, Tetrahalopalladate and tetraha loplatinate catalysts ef- 51]Int Cl 'C07c 67/00 fectively catalyze the preparation of allyl esters ofcar- 58] Fie'ld 475 N boxylic acids in the reaction between allylhalides and 260/485 N, 410.9 N, 476 R salts of carboxylic acids.

9 Claims, No Drawings PREPARATION OF ALLYLIC ESTERS WITH PALLADATE ANDPLATINATE CATALYSTS FIELD OF THE INVENTION This invention relates to amethod of preparation of esters of carboxylic acids. In another aspect,it relates to catalysts to improve the reaction of allyl halides withsalts of carboxylic acids.

DESCRIPTION OF THE PRIOR ART Heretofore, it has been recognized thatallyl halides react with alkali metal salts of carboxylic acids, usuallyat elevated temperatures, to form the corresponding esters. However,yields generally have been low, with conversion rates for theesterification process slow, consequently requiring excessive residencetimes in the reactors.

While the reaction of allyl halides with the carboxylic acid salts hasbeen a general method of esterification in the teachings of organicchemistry, commercial success has been wanting or limited, awaitingdiscovery of methods sufficient to increase yields and with swifter,surer reactions. Amines, quaternary ammonium halides, and the like, havebeen used as catalysts, though with limited efiectiveness.

Other methods of esterification are available, usually involvingmultiple steps, or relatively expensive or difficult to handle reagentssuch as the acid halides. Such processes have shortcomings compared tothe simplicity and ease of using a direct reaction of an allyl halidewith a carboxylic acid salt.

SUMMARY OF THE INVENTION I have discovered that the reaction of analkali metal hydrocarbon carboxylate with an allyl monohalide can beeffectively catalyzed by the use of certain catalysts, specificallytetrahalopalladate or tetrahaloplatinate catalysts.

It is an object of my process and catalyst to provide for improvedpreparation of esters of hydrocarbon carboxylic acids. A further objectof my invention is to provide more efficient methods for increasedyields of allyl esters of hydrocarbon carboxylic acids.

DETAILED DESCRIPTION OF THE INVENTION The tetrahalopalladate andtetrahaloplatinate catalysts of my invention can be represented by M TXM is ammonium, or is an alkali metal such as lithium, sodium, potassium,rubidium, or cesium. T is platinum or palladium. X is a halogen, and isfluorine, chlorine, bromine, or iodine. These tetrahalopalladate andtetrahaloplatinate catalysts are not simply double salts of an alkalimetal halide with such as palladous halide. Instead, a PdX and theequivalent tetrahaloplatinate radical actually are separate complexradicals.

Examples of my catalysts include lithium tetraiodopalladate, sodiumtetrabromoplatinate. potassium tetrachloropalladate, rubidiumtetrafluoroplatinate, cesium tetraiodopalladate, and ammoniumtetrabromoplatinate. Preparation of suitable catalysts useful in myinvention is disclosed in such references as Holtslaw, J r., H. F., 8Inorganic Syntheses 234, McGraw-Hill (New York 1966).

The esterification reaction to which I refer is a reaction between analkali metal hydrocarbon carboxylate containing up to four carboxylategroups with an allyl monghalide:

The number of carboxylate groups can range from I to 4, as representedby n within the formulas above, and n also is the valence of R. R ishydrogen or hydrocarbyl, and when hydrocarbyl, is saturated acyclic,saturated cyclic, aromatic, or alkyl-substituted aromatic in which theremay be as many'as three alkyl substitutions per aromatic group. The Rcan have up to 20 carbon atoms per R group, and, of course, will have avalence of n. R is hydrogen or alkyl, and as many as three of the Rradicals can be alkyl, with up to as many as six carbon atoms in thetotal of all R groups. M and X are as defined above relative to mycatalysts.

The mole ratio of alkali metal carboxylate group to the allyl monohalideis in the range of 0.01:1 to 10:1, preferably 05:1 for most advantageousoperation. From 0.1 to 100 moles of catalyst can be employed per 100moles of carboxylate group, through preferably in the range of 0.5 to 10moles per 100 moles of the carboxylate group are employed and result insuitable efficiency and conversion.

Temperatures in the range of 0 to 90 C. are employed in theesterification reaction with the catalysts of my invention. Temperatureswithin the range of 20 to C. are found quite effective. Pressures shouldbe sufficient to maintain the reactants and admixtures thereofsubstantially completely in the liquid phase, and usually will be in therange of 0.5 to 10 atmospheres. Atmospheric pressure often is aconvenience and generally quite suitable. Reaction times sufi'icient toeffect the degree of conversion should be employed. Normally, reactiontimes in the range of 1 minute to 24 hours are satisfactory. Preferably,the esterification should be effected substantially completely in theabsence of water, i.e., under essentially anhydrous conditions so as tominimize undesirable side reactions. However, minor traces of waternormally found associated with the reactants do not interfere unduly.

Upon completion of the desired degree of reaction, the ester producedcan be recovered in any conventional manner. Any of the ordinarytechniques known to the art for separation, such as filtration,stripping, solvent extraction, selective precipitation, and the like,can be employed as may be necessary or convenient.

The allylic esters produced in the processes of my invention arevaluable products for wide commercial use as solvents, in lubricatingoils, or for subsequent polymerization to valuable polyesters. Theesters can be converted to epoxy compounds and employed with epoxy resincuring agents to form valuable adhesives, coatings, and the like. Suchcompositions also can be employed as plasticizers for synthetic resinsand the like.

EXAMPLE The following example should be considered as illustrative andnot as limiting the scope of my invention.

To a stirred reactor were added 8.2 g (gram) (0.1 mole) of dry(anhydrous) powdered sodium acetate, 9.2 g (0.12 mole) allyl chloride,and 50 ml (milliliters) of dimethylformamide as diluent. No catalyst wasused. The mixture was heated to a temperature of approximately 65 C.,and maintained at such temperature for approximately 3 hours. Theadmixture subsequently was cooled to room temperature.

Analysis of a portion of the reaction products by gas liquidchromatography determined that only 20 mole per cent of the allylchloride had been converted to allyl acetate.

A solution of freshly distilled allyl chloride (4.6 g, 0.06 mole) inN,N-dimethylformamide (25 ml) was added to 4.1 g (0.05 mole) sodiumacetate. To this mixture was added 1.69 g (0.005 mole) of potassiumtetrachloropalladate as catalyst. The resulting admixture was stirred atroom temperature, and samples were removed each 30 minutes and analyzedby gas liquid chromatography. The analyses indicated complete conversionof the stoichiometric amount of allyl chloride (0.05 mole) to allylacetate within 2 hours reaction time.

Thus, comparison of the run using one of my catalysts, versus the-runwithout a catalyst, shows the high conversion obtained by the use ofcatalysts according to the process of my invention.

Certainly, the example given above illustrating some of the reactantspossible within the scope of my invention and according to the processof my invention should not be considered as limiting in any way, butonly illustrative of the compound types effective and useful.

Alkali metal hydrocarbon carboxylates including both monocarboxylates aswell as polycarboxylates useful according to the process of my inventioninclude:

sodium benzoate,

disodium isophthalate,

potassium formate,

lithium acetate,

rubidium decanoate,

cesium 3-methyloctanoate potassium cyclopentanecarboxylate,

sodium 4-toluenecarboxylate,

lithium 3,5-xylenecarboxylate,

tripotassium l,2,3-benzenetricarboxylate tetrasodium1,2,4,5-benzenetetracarboxylate disodium 1,8-octanedicarboxylate,

trisodium 1 ,3 ,6-hexanetricarboxylate,

tetrasodium 1,2,7,8-octanetetracarboxylate,

tetrasodium 1,2,4,5-cyclooctanetetracarboxylate,

sodium cycloeicosanecarboxylate,

sodium eicosanecarboxylate,

sodium 2-naphthalenecarboxy1ate,

potassium 2,4,6-tributylbenzenecarboxylate,v

tetrapotassium 1 ,10, 1 l ,20-eicosanetetracarboxylate,

tetralithium 1 ,4,8, 1 2-cycloeicosanetetracarboxylate,

tetrapotassium 2,3,6,7-anthracenetetracarboxylate,

tetrasodium 2,3,6,7-anthracenetetracarboxylate, and the like.

Allyl monohalides which can be employed according to the process of myinvention include:

3-chloro-1Propene,

3-ch1oro-1 -butene,

1bromo-2-nonene,

2-bromomethyl-l -octene,

3-iodo-1-nonene, 3 -fiuoro-2,3-diethyl- 1 -pentene,5-chloro-4-ethyl-3-heptene, 3-ch1oromethyl-4-ethy1-3-hexene,3-bromo-3-propyl-l-hexene, 2-( 1-ch1oropropy1)-1-hexene,4-iodo-2-methyl-2-octene, 4-iodo-2-methyl-2-octene, l -fluoro-2-pentene,2-chloromethyl- 1 -butene, and the like.

It is frequently desirable for the reactions I have described to beeffected in the presence of a gas which is substantially completelynonreactive in the reaction environment. Such gases as nitrogen, or arare gas such as helium, neon, argon, or krypton, or a lower paraffinhydrocarbon such as ethane, and the like, can be employed. I

The esterification reaction usually are effected in the absence of addeddiluents, though where desired for various purposes reaction diluentscan be employed in amounts which can comprise as much as percent byweight of the reaction medium. Examples of materials which can besuitably employed as diluents include acetone, methyl ethyl ketone,methyl isobutyl ketone, tetrahydropyran, cyclohexanone, tetrahydrofuran,cyclododecanone, N-methylpyrrolidone, sulfolane, dioxane,dihydrocarbylamides such as N,N'-dimethylformamide andN-methyl-N-phenylformamide, acetonitrile, propionitrile, and the like,and even mixtures if desired.

Reasonable variations and modifications are possible within the scope ofmy disclosure without departing from the scope and spirit thereof.

1 claim:

1. A process for preparing esters of hydrocarbon carboxylic acids whichcomprises reacting a hydrocarbon carboxylate with at least one allylmonohalide in the liquid phase at 0 to 90 C. in the presence of aneffec-- tive amount of at least one catalyst selected fromtetrahalopalladates and tetrahaloplatinates wherein said catalyst is MTX wherein M is ammonium, lithium, sodium potassium, rubidium, orcesium; T is platinum or palladium; X is fluorine, chlorine, bromine, oriodine; said hydrocarbon carboxylate is wherein R is hydrogen orhydrocarbyl containing up to 20 carbon atoms wherein said hydrocarbyl isalkyl,

cycloalkyl, aryl or alkyl substituted aryl containing up to 3 alkylsubstituents; n is an integer of from 1 to 4 inclusive and is equal tothe valence of R; and said allyl monohalide is R '2C CR'CR 'X wherein Ris hydrogen or alkyl such that the carbon atoms in the total of all Rgroups is from 0 to 6.

2. The process according to claim 1 wherein said M TX,tetrahalopalladate or tetrahaloplatinate catalyst is employed in anamount of from 0.1 to moles of said catalyst per 100 moles ofcarboxylate group in said hydrocarbon carboxylate.

3. The process according to claim 2 wherein the mole ratio of saidhydrocarbon carboxylate to said allyl monohalide is in the range of from0.011 to 10: l

4. The process according to claim 1 wherein the reaction is carried outat a temperature of 20 to 80 C. and a reaction time of from 1 minute to24 hours.

5. The process according to claim 1 wherein the reaction is carried outin the presence of a non-reactive gas in the reaction environment.

6. The process according to claim 5 wherein said non-reactive gas isnitrogen, a rare gas, or lower paraffin hydrocarbon.

7. The process according to claim 1 wherein the reaction is carried outin the presence of a diluent comprising up to 95 weight per cent of thetotal reaction medium wherein said diluent is selected from the groupUNlTE STATES PATENT oFFIcE CERTEFECATE OF CQRRHJTWN Patent 3,700,724Dated October 24, 1972 Donnie G. Brady lnventor(s) It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 4, line 57, the formula should appear as shown below:

1 1 1 R C CR CR X Signed and Sealed this 10th day of April 1973 (SEAL)Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM P0105? uscoMM-Dc 60376-5 69 U.S. GOVERNMENT PRINTINGOFFICE: 969 0-35633L

2. The process according to claim 1 wherein said M2TX4tetrahalopalladate or tetrahaloplatinate catalyst is employed in anamount of from 0.1 to 100 moles of said catalyst per 100 moles ofcarboxylate group in said hydrocarbon carboxylate.
 3. The processaccording to claim 2 wherein the mole ratio of said hydrocarboncarboxylate to said allyl monohalide is in the range of from 0.0:1 to10:1.
 4. The process according to claim 1 wherein the reaction iscarried out at a temperature of 20* to 80* C. and a reaction time offrom 1 minute to 24 hours.
 5. The process according to claim 1 whereinthe reaction is carried out in the presence of a non-reactive gas in thereaction environment.
 6. The process according to claim 5 wherein saidnon-reactive gas is nitrogen, a rare gas, or lower paraffin hydrocarbon.7. The process according to claim 1 wherein the reaction is carried outin the presence of a diluent comprising up to 95 weight per cent of thetotal reaction medium wherein said diluent is selected from the groupof: acetone, methyl ethyl ketone, methyl isobutyl ketone,tetrahydropyran, cyclohexanone, tetrahydrofuran, cyclododecanone,N-methylpyrro-lidone, sulfolane, dioxane, N,N-dimethylformamide,N-methyl-N-phenyl formamide, acetonitrile, propionitrile and mixturesthereof
 8. The process according to claim 7 wherein said allylmonohalide is allyl chloride, said hydrocarbon carboxylate is sodiumacetate, and said catalyst is potassium tetrachloropalladate.
 9. Theprocess according to claim 8 wherein said diluent is N,N''-dimethylformamide.